Agricultural machines such as high-clearance sprayers typically have an operator cab and an engine compartment housing various components for the machine, such as an engine and drive system. To keep the engine cool, an engine cooling package fan is typically provided in the engine compartment. The engine cooling package fan can draw ambient air into the engine compartment housing to cool through heat exchangers to perform numerous cooling functions. This can include cooling engine coolant, hydraulic oil, charged air, and the like.
However, rotating an engine cooling package fan requires power which, in turn, causes a parasitic power loss in the system. For example, for engine cooling package fans that are hydraulically driven, rotating such fans reduces the hydraulic power that is available for other components in the hydraulic system.
To reduce such parasitic effects, some cooling package fans are operated at variable speeds. Such variable speed fans can be operated at slower speeds to consume less power when less cooling is needed, and at faster speeds which may consume more power when more cooling is needed. The amount of cooling needed can be determined by sensed temperature(s) in the engine compartment, such as with respect to engine coolant, hydraulic oil and/or charged air.
However, when an Air Conditioning (AC) unit of Heating, Ventilation and Air Conditioning (HVAC) system as running, such variable control is deactivated and the cooling package fan is operated at full speed. As a result, with a substantial amount of in-field agricultural equipment operation running during warm weather, operation of the AC results in a substantial power loss in the system due to the continuous parasitic loss caused by the cooling package fan. This can defeat the purpose of variable speed capability for the fan. A need therefore exists for an improved system which eliminates one or more of the foregoing disadvantages.